Device for the photoelectric marking and reading of tools for NC machine tools

ABSTRACT

A device for photoelectric marking and reading, useful with tools for NC machine tools equipped with a tool magazine and device for an automatic tool exchange. The device includes a system of coding fields optically differentiated by a different transmittance or reflectance of light, and comprises a coding plate provided with coding fields arranged in several lines and reading phototransmitters that are arranged in one line in a reading head. In the reading head, opposite the line of the phototransmitters, there is situated a corresponding line of light sources so, that one individual light source corresponds to each phototransmitter, the light sources and their corresponding phototransmitters together forming a reading couples, the number of these reading couples corresponding to the number of coding spots in one line of the coding plate.

United States Patent Kepka et al. Dec. 23, 1975 DEVICE FOR THE PHOTOELECTRIC 3,576,540 4/1971 Fair et al. 235/6l.l1 MARKING A D READING OF TOOLS FOR 3,621,265 11/1971 Berler 250/569 3,702,471 11/1972 Kennedy et al. 235/61.1l NC MACHINE TOOLS 3,729,618 4/1973 Drew et al 235/6l.ll E [75] Inventors: Jiri Kepka, Prague; Karel Kovarik, 3,786,236 1/1974 Sato et a1 250/569 celakovice; Bohuslav Loun; 3,822,384 7/1974 Chapron et al. 250/239 Jaromir Zeleny, both of Prague, all of Czechoslovakia Primary Examiner-Stanley M. Urynowicz, Jr.

[73] Assignee: Vyzkumny ustav obrabecich stro iu a [57] ABSTRACT obrabem, Prague, Czechoslovakla A device for photoelectric marking and reading, use- Flledi y 1974 ful with tools for NC machine tools equipped with a [21] APP] NO: 472 286 tool magazine and device for an automatic tool exchange. The device includes a system of coding fields optically differentiated by a different transmittance or [30] Foreign Application Priority Data reflectance of light, and comprises a coding plate pro- May 29, 1973 Czechoslovakia 3866-73 vided with Coding fields arranged in Several lines and reading phototransmitters that are arranged in one [52] US. Cl 235/6111 E; 250/569; 250/239 .line in a reading head- In the reading head, pp [51] Int. Cl. G06K 7/10 h n f h ph r n mi rs, there is situated a [58] Field of Search 250/555, 239, 566, 569; corresponding line of light sources so, that one indi 235 /61 1 1 E, 151 11; 214/1 PE vidual light source corresponds 'to each phototransmitter, the light sources and their corresponding photo- [56] References Cited transmitters together forming a reading couples, the UNITED STATES PATENTS number of these reading couples corresponding to the 3,226,833 1/1966 Lemelson 235/61.1l number of coding spots m one me of the codmg plate 3,297,879 1/1967 Meyer 250/555 5 Claims, 3 Drawing Figures FIXED HOLDE/R 70 l3 l3 READING HEAD I l 3 x Zb mmn OI QMXE mm Dec. 23, 1975 DEVICE FOR THE PHOTOELECTRIC MARKING AND READING OF TOOLS FOR NC MACHINE TOOLS The invention relates to a photoelectric marking and reading device, such device being especially useful with tools for NC machine tools that are equipped with a tool magazine and a device for an automatic tool exchange, e.g. tooling centers.

A coding of tools for NC machine tools equipped with a coded tool magazine has been carried out until now either (1) mechanically by a system of stops that control a system of switches, or (2) contactless-electromagnetically, viz. by a system of small permanent magnets situated on the tool that pass a system of switching coils. A limited service life of switching elements and its large dimensions are a disadvantage of the first system. A large surface needed for situating that coding elements on a tool is a disadvantage of the second system, as it makes tool holders more complicated, heavier andit limits the numerical range of a code. In fact, it is sorely needed feature that coding plates shall have minimum dimensions.

There is also known a photoelectric system and device for code marking the reading, which obviates some of the above mentioned disadvantages, in which the coding is carried out by means of a coding plate with a system of coding fields of a different optical reflectance of transmittance of light delivered by a light source situated in a reading head which also includes a system of reading phototransmitters. All coding fields are read simultaneously, i.e. in a parallel principle. This parallel photoelectric system is in every respect better than the mechanical and electromagnetical system, especially with respect to the numerical contents of a code and all dimensions of the device. But with respect to uptodate requirements for a numerical range of a code, e.g. l and more, the dimension problems also come into question, as an individual phototransmitter is needed for each coding field; this increases both the dimensions and the price of a reading device.

Some of the above-mentioned disadvantages are obviated by the device for photoelectric marking and reading according to the invention. Such device comprises a coding plate provided with coding fields arranged in several lines, and reading phototransmitters that are arranged in one line in a reading head. In a reading head there may be situated, opposite the line of the phototransmitters,'.a corresponding line of light sources, so that one individual light source corresponds to each phototransmitter; so that together they form a reading couple, the number of these reading couples corresponding to the number of coding spots in one line of the coding plate. The whole reading head may be fixed to its clamping holder and movable in the plane which is at right angles to the direction of the functional movement being limited either by springs or by stable stops, or by both of them. The reading head during the reading may be directed to the coding plate, which is fixed to a tool holder, by one or more guides having narrowed guiding ends engaged in guiding grooves. During a functional movement, the reading head with the line of the reading couples pass across the lines of the coding fields and reads them in a manner similar to a reader of a punched tape, viz. serialparallely.

As light sources there may be advantageously employed either miniature filament bulbs or so-called radiators, ev. emitting diodes, e.g. galium arsenid diodes, emitting an invisible infrared radiation. These radiators, as well as the respective photosensors e.g. silicon phototransistors, are now produced with such miniature dimensions that their couple arrangement is advantageous both for design and production so that much smaller reading heads may be made than when applying one common light source. The proper reading of coding fields may be carried out either in a reflectance system, wherein the fields are differentiated by a different light reflectance, or in a transmittance system wherein the fields are made as holes or solid spots in an opaque material.

A device according to the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a view in plan of a coding plate 1;

FIG. 2 is a schematic view of an arrangement of a reading head together with a coding plate and the head of a tool holder in a transmittance system; and

FIG. 3 is a diagram of a position arrangement of light 'sources and phototransmitters with respect to the coding plate in the arrangement for a reflectancesystem.

In FIG; 1 there is drawn a coding plate 1 with five vertical lines of coding fields 2.. Each of these lines in a transmittance system includes six coding fields 2 represented either by through-holes or solid spots. Instead of a transmittance system, there :may be employed a reflectance system having a coding plate with small mirror surfaces and dull ones. A functional movement of the reading head is in both cases cross with respect to the mentioned vertical lines, as shown by an arrow in FIG. 1.

In FIG. 2 there is shown an example of a reading head including a line of phototransmitters 3 and respective line of light sources 4, e.g. radiators. Both vertical lines are situated in plates 13 fixed in the reading head. The coding plate 1 with vertical lines of coding fields 2, represented in this case either by through-holes or solid spots, passes between the mentioned lines of the transmitters 3 and light sources 4. The functional movement of the reading head with respect to the coding plate 1 is in this case rectangular or normal to a-front view plane. The coding plate 1 is fixed in a head of a tool holder 5 which is provided on both sides with grooves 6. In these centering grooves 6 the narrowed ends of guide bars 7 are engaged in these centering grooves 6 during the functional movement. Grooves 12 are formed in opposite side walls of a clamping holder 10. Springs 9, by means of which the reading head is resiliently mounted in the clamping holder 10, engage oppositely extending guide members 11 on the reading head. Elastic deviations of the reading head with respect to the clamping holder 10 are limited by engagement between the guides 11 and the side wall 12a and the upper end lower walls 12b and 12c of the respective recess 12. This insures a correct position of reading couples of the phototransmitters 3 and radiators 4 with respect to the coding plate 1 in the moment of reading, as well as a correct reading even in case that the tool holder is not accurately situated in the magazine.

If an advantageous code is applied, a coding in the range of five and more decades may be carried out in the coding plate, because each line of field's 2 of the coding plate 1 represents one decade. This is suitable for any requirements for marking tools for machine tools, and this range may eventually even be increased. Applying any other system known till now, one cannot accomplish such small dimensions of the coding plate 1 and coding head. This contactless system of reading insures a maximum service life of the device. Eventual fouling of the coding plate that may endanger a reliability of reading may be automatically removed by pressure air which passes through the holes in the reading head.

In FIG. 3 there is shown diagrammatically an arrangement of the above-mentioned reflectance system, which may be more convenient in some cases than the transmittance system. Light radiated by source 4' is either reflected or not by coding fields 2 to coding plate 1' of phototransmitters 3. The rest of the arrangement may be the same as that in FIG. 1.

Although the invention is illustrated and described with reference to one preferred embodiment thereof, it is to be expressly understood that it is in no way limited to the disclosure of such a preferred embodiment, but is capable of numerous modifications within the scope of the appended claims.

What is claimed is:

1. In a machine tool equipped with a tool magazine device for an automatic tool exchange, the improvement which comprises a holder for a tool to be exchanged, a coding plate affixed to the tool holder, a clamping holder, and a reading head, means mounting the reading head on the clamping holder, the tool holder and the coding plate mounted thereon being slidably movable past the reading head to permit the reading of the coding plate by the reading head, and at least one guide comprising inter-fitting and relatively slidable parts on the tool holder and the reading head to position such parts relative to each other.

2. Apparatus according to claim 1, wherein the means mounting the reading head permits limited movement of the reading head relative to clamping holder in a plane normal to the direction of sliding movement of the reading head relative to the clamping holder, and means limiting such movement in said plane normal to said direction of sliding movement of the reading head.

3. Apparatus according to claim 2, comprising means yieldably urging the reading head to a central position in said plane normal to the direction of the sliding movement of the reading head.

4. Apparatus according to claim 1, wherein the coding plate is provided with light receiving coding field arranged in several lines, and the reading head is provided with reading photo-transmitters that are arranged in one line.

5. Apparatus according to claim 4, wherein in the reading head, which is disposed opposite the line of the photo-transmitters there is disposed a corresponding line of light sources, one individual light source corresponding to each phototransmitter so that together they form a reading couple, the number of such reading couples corresponding to the number of coding fields in one line of the coding plate. 

1. In a machine tool equipped with a tool magazine device for an automatic tool exchange, the improvement which comprises a holder for a tool to be exchanged, a coding plate affixed to the tool holder, a clamping holder, and a reading head, means mounting the reading head on the clamping holder, the tool holder and the coding plate mounted thereon being slidably movable past the reading head to permit the reading of the coding plate by the reading head, and at least one guide comprising inter-fitting and relatively slidable parts on the tool holder and the reading head to position such parts relative to each other.
 2. Apparatus according to claim 1, wherein the means mounting the reading head permits limited movement of the reading head relative to clamping holder in a plane normal to the direction of sliding movement of the reading head relative to the clamping holder, and means limiting such movement in said plane normal to said direction of sliding movement of the reading head.
 3. Apparatus according to claim 2, comprising means yieldably urging the reading head to a central position in said plane normal to the direction of the sliding movement of the reading head.
 4. Apparatus according to claim 1, wherein the coding plate is provided with light receiving coding field arranged in several lines, and the reading head is provided with reading photo-transmitters that are arranged in one line.
 5. Apparatus according to claim 4, wherein in the reading head, which is disposed opposite the line of the photo-transmitters there is disposed a corresponding line of light sources, one individual light source corresponding to each phototransmitter so that together they form a reading couple, the number of such reading couples corresponding to the number of coding fields in one line of the coding plate. 